\documentclass{article}
\usepackage[x11names, rgb]{xcolor}
\usepackage[utf8]{inputenc}
\usepackage{tikz}
\usetikzlibrary{snakes,arrows,shapes}
\usepackage{amsmath}
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\usepackage[active,tightpage]{preview}
\PreviewEnvironment{tikzpicture}
\setlength\PreviewBorder{0pt}%
\usetikzlibrary{automata}%

\begin{document}
\pagestyle{empty}
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%
%

\enlargethispage{100cm}
% Start of code
\begin{tikzpicture}[>=latex',join=bevel,]
\tikzstyle{every state}=[draw=blue!50,very thick,fill=blue!20]%
\node (q0) at (40bp,282bp) [state] {$q_{0}$};
  \node (q1) at (40bp,18bp) [state] {$q_{1}$};
  \node (q3) at (73bp,106bp) [state] {$q_{3}$};
  \node (q2) at (73bp,194bp) [state] {$q_{2}$};
  \draw [->] (q3) ..controls (73bp,130bp) and (74bp,136bp)  .. (74bp,142bp) .. controls (74bp,150bp) and (74bp,158bp)  .. node[auto] {$\tau$} (q2);
  \draw [->] (q3) ..controls (62bp,76bp) and (55bp,59bp)  .. node[auto] {$\tau$} (q1);
  \draw [->] (q2) ..controls (59bp,167bp) and (56bp,154bp)  .. (58bp,142bp) .. controls (59bp,139bp) and (60bp,136bp)  .. node[auto] {$\overline{a}$} (q3);
  \draw [->] (q0) ..controls (51bp,252bp) and (58bp,235bp)  .. node[auto] {$\tau$} (q2);
  \draw [->] (q0) ..controls (38bp,250bp) and (37bp,230bp)  .. (37bp,212bp) .. controls (35bp,156bp) and (35bp,143bp)  .. (37bp,88bp) .. controls (37bp,74bp) and (38bp,59bp)  .. node[auto] {$\tau$} (q1);
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\end{tikzpicture}
% End of code

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\end{document}
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